Liquefied-gas cartridge with dispensing valve

ABSTRACT

A liquefied-gas cartridge with dispensing valve is described which comprises, in the liquid phase of the liquefied gas contained within the cartridge, an agent which, on cooling of the liquefied gas in consequence of evaporation of the liquid phase whilst the valve remains open, releases heat to the liquefied gas. The agent preferably contains, or consists of, a substance which is liquid at room temperature and which has a solidification temperature in the range of about + 10*C + 20*C and which is either practically insoluble in the propellant and added directly thereto, or which is enclosed by a capsule of good heat-conductivity. Butane-1,4-diol, glacial acetic acid or acetophenone are suitable as such agents.

United States Patent [191 [111 3,863,813

Metzner Feb. 4, 1975 [5 LIQUEFlED-GAS CARTRIDGE WITH 3,472,426 10/1969 Nesin 222/146 HA DISPENSING VALVE $632,516 1/1972 [75] Inventor: l-lelmut Metzner, Pfeffingen,

Switzerland [73] Assignee: Ciba-Geigy Corporation, Ardsley,

[22] Filed: Apr. 22, 1974 [21] Appl. No.: 462,693

[30] Foreign Application Priority Data Apr. 25, 1973 Switzerland 5883/73 Jan. 31, 1974 Switzerland 1333/74 [52] U.S. Cl 222/146 HA [51] Int. Cl B67d 5/62 [58] Field of Search 252/1883 R; 222/146 HA, 222/192 [56] References Cited UNITED STATES PATENTS 3,137,416 6/1964 Shepherd et al 222/192 3,325,056 6/1967 Lewis 222/146 HA X Antonelli et a1. 222/146 HA Primary Examiner-Stanley H. Tollberg Assistant Examiner-John P. Shannon [57] ABSTRACT A liquefied-gas cartridge with dispensing valve is described which comprises, in the liquid phase of the liquefied gas contained within the cartridge, an agent which, on cooling of the liquefied gas in consequence of evaporation of the liquid phase whilst the valve remains open, releases heat to the liquefied gas. The agent preferably contains, or consists of, a substance which is liquid at room temperature and which has a solidification temperature in the range of about 10C 20C and which is either practically insoluble in the propellant and added directly thereto, or which is enclosed by a capsule of good heat-conductivity. Butane-1,4-diol, glacial acetic acid or acetophenone are suitable as such agents.

13 Claims, 2 Drawing Figures PATENTED FEB 4W5 SHEET 2 [IF 2 LlQUEFlED-GAS CARTRIDGE WITH DISPENSING VALVE The invention relates to a pressurised liquefied-gas cartridge with dispensing valve.

Pressure packs are already known, e.g., for spraying liquid products in aerosol form, in which the liquefied gas serving as propellant, such as, e.g., dichlorodifluoromethane and other Freons, dimethyl ether, propane, etc., and the product to be sprayed are located in separate containers, and whereby, with the opening of a dispensing valve, the gas phase of the liquefied gas is discharged from the propellant container through a dispensing nozzle, preferably a Venturi spray nozzle. In this case, the liquid phase of the propellant in the propellant container evaporates initially to the extent that the gas phase is escaping from the said container. There is however simultaneously occurring, in consequence of the high heat of evaporation of the liquefied gas (for dichlorodifluoromethane this is 39.86 cal/g) a severe cooling of the liquid phase in the container, and this cooling is accompanied by a pressure drop in the container. This in turn leads to a decrease of the rate of evaporation and hence to a reduction in the flow of gas passing through the dispensing nozzle. lnthe case of a Venturi nozzle, there is then also a lowering of its suction efficiency, and the emission of the product being sprayed diminishes and finally ceases completely.

Also with the use of liquefied gas for other purposes than for aerosol manufacture, e.g., as fuel in cookers or igniters, for soldering-iron heating, and so forth, where no special dispensing nozzle is required, the described temperature drop in the liquefied gas causes a clear reduction in the flow of gas and a shortening of the spray ing time of the individual discharge. Suitable liquefied gases for this purpose are, in particular, butane and isobutane, optionally also propane.

There is now provided by virtue of the present invention a pressurised liquid-gas cartridge with a dispensing valve and, optionally, with a discharge nozzle, prefera-. bly a Venturi nozzle, which cartridge is suitable for a more prolonged discharge of gas. The said new liquefied-gas cartridge is one in which the above-described phenomenon of temperature drop in the liquid phase of the liquefied gas inside the cartridge is reduced to the greatest possible degree, or appreciably retarded.

This is achieved according to the invention by means of a pressurised liquid-gas cartridge with dispensing valve, the said cartridge being characterised by the presence, in the liquid phase of the liquefied gas contained within the cartridge, of an agent which, on cooling of the liquefied gas in consequence of the evaporation of the liquid phase during the time the valve is open, releases heat to the liquefied gas.

This release of heat counteracts the cooling of the liquefied gas and thus reduces or supresses the cooling phenomenon. The heat-releasing agent consists, in particular, of a substance which is liquid at room temperature and which has a solidification temperature in the range of about to 30C, preferably from about C to about C, or of a mixture of such substances.

Preferably, the substance releasing heat on solidifying is practically insoluble in the liquefied gas and can thus be added directly to it. Alternatively, the said substance can be enclosed in a good heat-conducting capsule, and the capsule thus prepared can then be introduced into the liquefied gas.

The agent releasing heat can contain, in addition to the substance giving up heat on solidification, an amount of an auxiliary capable of preventing undercooling-of the said substance.

Such substances are preferred of which, on solidification, each gram releases at least 30 calories. It is preferable to choose a substance which, on solidification, releases more than 30 and as far as possible more than 45 60 calories per gram.

A substance that can be added direct to the liquefied gas, e.g., to a compound of the Freon class (e.g., dichlorodifluoromethane, trichlorofluoromethane or chlorotrifluoromethane), dimethyl ether, propane, butane or isobutane, and which satisfies the other conditions mentioned above, is butane-l.4-diol.

' ulated form. Advantageously, there is added, either direct or enclosed by an aluminium capsule, to an amount of liquefied gas of, for example, 50 ml an amount of about 5 g of substance releasing heat on solidfying (i.e., a weight ratio of ca. 10 1).

In the storage time between two periods of applica-' tion sufficient heat is transferred to the propellant cartridge from the surrounding medium to again warm the liquefied propellent gas and to thus again melt the solidi fied substance contained loose or encapsulated therein.

Furthermore, the pressurised liquefiedgas cartridge can be provided with a discharge nozzle, particularly a Venturi nozzle, in addition to the dispensing valve.

A particularly significant extension of the spraying time is obtained with a pressurised liquefiedgas cartridge of the above-described type in which the weight ratio between liquefied gas and heat-releasing substance is at least about a third less than 10 1 l, i.e., at most 7 1.This weight ratio is preferably 5 l to 3 l. As a result thereof, the spraying time is lengthened by a factor of at least two and a half to three.

The smaller total amount of propellant contained, with a given volume for the liquefied-gas cartridge, in consequence of the higher content of heat-releasing substance can be easily accepted since, in the case of later aerosol sprayers with separate propellant cartridge, the said cartridge is no longer located inside the product container but is mounted separate therefrom and connected to it, in the storage position, by way of a connecting piece, so that it is easily exchangeable. If the content of such a propellant cartridge is exhausted while there is product still present in the product container, then the emptied cartridge can be simply exchanged for a full one, and the remainder of the product discharged from its container, whereby the length of time of the separate sprayings can be quite two and a half to three times greater than that of a spraying effected by a propellant alone without use of a heatreleasingsubstance in the liquefied-gas cartridge.

The following apparatus, which is'schematically illustrated in FIG. 1 of the attached drawing, serves to establish the practical effects of using heat-releasing substances as additives in the liquefied gas in a propellant cartridge for aerosol sprayers. FIG. 2 shows the curves plotted from the experimental results.

A cyclindrical liquefied-gas cartridge 1 in the apparatus according to FIG. 1 is made of aluminium. It weighs 1 1.5 g and has an internal diameter of 30 mm and an internal height to the neck 2 of 85 mm. Up to the start of the shoulder-forming neck 2 the cartridge has an internal volume of 50 ml. In the neck 2 is mounted an outlet valve 3 with an actuating head 4, and thereto is fitted a valve shaft (not shown). A spray nozzle 5 of the Venturi type is incorporated in the actuating head 4. The arrangement of valve and spray head is known, for example, from the Swiss Pat. No. 504,898. The narrowest outlet diameter of the valve in this this series of tests is designed to be 0.3 mm.

To valve 3 is connected a suction tube 6, the free end of which is immersed in the liquid product to be sprayed, which is accomodated in a container 7 separate from the liquefied-gas cartridge. Water can be used as the product to be sprayed in the tests described in the following.

Passing through the wall of the liquefied-gas cartridge l is a thermocouple element 8, which continuously measures the temperature within the liquid phase of the liquefied gas, and this temperature is continuously plotted on a temperature recorder 9. The temper- Example 2 I0 g of glacial acetic acid is placed into a narrow aluminium capsule. The capsule is closed with a rubber stopper and then inserted into the cartridge I. The cartridge is closed with the valve 3 and then charged with 35 g of dichlorodifluoromethane. The subsequent procedure is as described in Example I.

ature recorder, to which the thermocouple element 8 is connected, can be, for example, a Philipps multichannel recorder of the type PR 3500. Finally, the cartridge 1 contains a sponge 10 as an element absorbing liquefied gas; this sponge prevents in a known manner the liquid propellant from entering valve 3.

Experimental procedure The aluminium cartridge 1 is filled with the heatreleasing substance of the type given in the following examples, and thereupon charged under pressure with the liquefied gas; the filled cartridge is allowed to warm up to 20C (room temperature). The spray head is then pressed until the temperature within the liquid phase of the liquefied gas has fallen to 0C, and the time required therefore is measured. The multichannel recorder is simultaneously recording the temperature variation in the liquid phase of the liquefied gas. This temperature variation for the following three examples and for a control test is shown in the attached diagram (FIG. 2).

In addition to the spraying time required to effect cooling to 0C, there is also measured the amount of propellant consumed during this interval of time, as well as the amount of product (water) sprayed.

The following examples of tests with the described apparatus illustrate the invention without limiting its scope.

Example I 10 g of butane-1,4-diol is weighed into the cartridge 1. The sponge 10 is then introduced and the cartridge closed by means of the valve 3 and charged with g of dichlorodifluoromethane. After the cartridge has acquired room temperature, the thermocouple element 8 is connected to the multichannel recorder 9. The suction pipe 6 of the valve 3 is immersed in the water con- Example 3 10 g of l-bromohexadecane is weighed into an aluminium capsule; the capsule is then closed with a rubber stopper and inserted into the cartridge 1. The procedure otherwise is analogous to that described in Example 2.

Control Example Example I is repeated except that in this case no l,4- butanediol is used, and only the stated amount of dichlorofluoromethane inserted into the cartridge 1.

The attached diagram illustrates these results. The time in seconds on the X-axis is plotted against the temperature in C on the Y-axis.

Example 4 Into an aluminium propellant-cartridge weighing 11.5 g is inserted 3 ml of glacial acetic acid contained in a small aluminium capsule, together with some small iron beads to prevent an undercooling of the glacial acetic acid; the cartridge is then fitted with an outlet valve and subsequently charged with 50 g of Freon 12 (dichlorodifluoromethane).

The valve is open to allow a discharge of gaseous Freon 12 from the propellant cartridge.

A comparative test is carried out with the same experimental arrangement except that there is no aluminium capsule containing glacial acetic acid in the cartridge, which is charged this time with 54 g of Freon l2.

Incorporated in the experimental arrangement is a hermetically sealed thermometer immersed in the liquid Freon. In the following Table II are given the evaporated amount of Freon and the opening time in the course of which the temperature of the liquid Freon has decreased (a) by 5C and (b) by 10C. The employed Venturi nozzle is one having an outlet diameter at the narrowest point of 0.3 mm.

The test is also performed with a half-filled cartridge.

Table II claim 2, wherein the substance is practically insoluble (a) cooling by 5C (a) Cooling by 10C full cartridge half full cartridge liquefied-gas charge (Freon 12) 54 g 50 g 27 g 25 g glacial acetic acid 3 ml 3 ml amount of Freon l2 gas evaporated 3.36 g 7.05 g 2.0 g 5.8 g spraying time (sec.) 22.5 47 13.3 38.5 extension of spraying time (7e) ca. llO ca. I90

Similarly good results are obtained if a comparison be made, with respect to emission of gas under constant emission conditions,

A. between a cartridge fully filled with 55 g of dichlorofluoromethane and boiling beads and an equally large cartridge filled with 50 g of dichlorodifluoromethane, 5 g of butane-1,4-diol and the same amount of boiling beads as before, wherein the alcohol is added direct to the liquefied gas;

B. a comparison as under (A), except that the heat,-

releasing substance is 5 g of acetophenone;

C. a comparison as under (A), except that the heatreleasing substance is 4.9 g of butane-1,4-diol;

D. a comparison as under (A), except that the heatreleasing substance is 10 g of acetophenone.

In each of these tests, the substance contained in the capsule solidifies, with the release of heat, after an extended spraying time, in consequence of which the discharged amount of gas is greatly increased compared with the amount discharged in the same time without the presence of the heat-releasing substance.

What is claimed is:

l. A liquefied-gas filled cartridge with dispensing valve, comprising, in the liquid phase of the liquefied gas contained within the cartridge, an agent which, on cooling of the liquefied gas in consequence of evaporation of the liquid phase whilst the valve remains open, releases heat to the liquefied gas.

2. A liquefied-gas filled cartridge as described in claim 1, wherein the said agent contains, or consists of, a substance which is liquid at room temperature and which has a solidification temperature in the range of about +lOC to +C.

3. a liquefied-gas filled cartridge as described in in the propellant andis added directly to it.

4. A liquefied-gas filled cartridge described in claim 2, wherein the said substance is enclosed by a well heat-conducting capsule.

5. A liquefied-gas filled cartridge as described in claim 2 wherein the said agent comprises an additive preventing undercooling of the said substance.

6. A liquefied-gas filled cartridge as described in claim 2, wherein each gram of the said substance releases on solidification about 40 to calories to the liquefied gas 7. A liquefied-gas filled cartridge as described in claim 1, wherein the said substance is butane-l,4-diol, which is added directly to the liquefied gas.

8. A liquefied-gas filled cartridge as described in claim 1, wherein the said substance is glacial acetic acid, which is added in a heat-conducting capsule to the liquefied gas.

9. A liquefied-gas filled cartridge as described in claim 1 wherein the said substance is acetophenone, which is added in a heat-conducting capsule to the liquefied gas.

10. A liquefied-gas filled cartridge as described in claim 8, wherein the said capsule is made ofa well heatconducting metal that is not attacked by the substance.

11. A liquefied-gas filled cartridge as described in claim 10 wherein the said capsule is made of aluminum or silver.

12. A liquefied-gas filled cartridge as described in claim 1, wherein the weight ratio of liquefied gas to heat-releasing substance is at most 7 l.

13. A liquefied-gas filled cartridge as described in claim 12, wherein the weight ratio of liquefied gas to heat-releasing substance is 3 l to 5 l. 

1. A liquefied-gas filled cartridge with dispensing valve, comprising, in the liquid phase of the liquefied gas contained within the cartridge, an agent which, on cooling of the liquefied gas in consequence of evaporation of the liquid phase whilst the valve remains open, releases heat to the liquefied gas.
 2. A liquefied-gas filled cartridge as described in claim 1, wherein the said agent contains, or consists of, a substance which is liquid at room temperature and which has a solidification temperature in the range of about +10*C to +20*C.
 3. a liquefied-gas filled cartridge as described in claim 2, wherein the substance is practically insoluble in the propellant and is added directly to it.
 4. A liquefied-gas filled cartridge as described in claim 2, wherein the said substance is enclosed by a well heat-conducting capsule.
 5. A liquefied-gas filled cartridge as described in claim 2 wherein the said agent comprises an additive preventing undercooling of the said substance.
 6. A liquefied-gas filled cartridge as described in claim 2, wherein each gram of the said substance releases on solidification about 40 to 60 calories to the liquefied gas
 7. A liquefied-gas filled cartridge as described in claim 1, wherein the said substance is butane-1,4-diol, which is added directly to the liquefied gas.
 8. A liquefied-gas filled cartridge as described in claim 1, wherein the said substance is glacial acetic acid, which is added in a heat-conducting capsule to the liquefied gas.
 9. A liquefied-gas filled cartridge as described in claim 1 wherein the said substance is acetophenone, which is added in a heat-conducting capsule to the liquefied gas.
 10. A liquefied-gas filled cartridge as described in claim 8, wherein the said capsule is made of a well heat-conducting metal that is not attacked by the substance.
 11. A liquefied-gas filled cartridge as described in claim 10 wherein the said capsule is made of aluminum or silver.
 12. A liquefied-gas filled cartridge as described in claim 1, wherein the weight ratio of liquefied gas to heat-releasing substance is at most 7 :
 1. 13. A liquefied-gas filled cartridge as described in claim 12, wherein the weight ratio of liquefied gas to heat-releasing substance is 3 : 1 to 5 :
 1. 